为了研究LED光源在设施番茄育苗生产上的精准化利用。该试验以金鹏1号番茄植株为试材，研究了进入黑暗前LED远红光处理对番茄植株形态、激素含量、光合速率和矿质元素含量的影响。结果表明，当番茄植株进入黑暗前进行10 min远红光处理，番茄植株的株高及茎的鲜质量发生了明显变化，番茄植株的株高和茎的鲜质量随着远红光光照强度的增加而增加，当远红光的光照强度增加到10μmol/(m2·s)时番茄植株的株高和茎的鲜质量也达到了最大值。与对照相比，进入黑暗前进行时长10 min，光照强度为10μmol/(m2·s)的远红光处理后番茄植株叶片中的生长素和赤霉素3的含量显著上升；叶绿素和净光合速率显著降低；番茄植株茎中N含量显著降低，叶中P含量显著降低，K含量显著升高，根系中的N、P、K含量都显著增加。因此，可以通过调控黑暗前远红光的光照强度来精确调控番茄植株的株高，控制番茄的生长。%Light emitting diode (LED) is a new light source which has several unique advantages, including the ability to control the spectral composition, the relatively cool emitting surfaces and minimum heating. Therefore, the research of precision utilization of LED is very important for energy saving and accuracy control in protected vegetable growth. In this study, Jinpeng NO.1 tomato seedlings were used as the material. After germination, the same-sized plants were selected and transplanted to the LED growth chamber with a temperature of 25℃ during the day and 20℃ during the night, 12 h photoperiod, and 65% relative humidity. In the daytime, tomato seedlings were grown under white LED at an illumination intensity of 168µmol/(m2·s). The ratio of red light (655-665 nm) to far red light (725-735 nm) in white LED was 6.42. Before the tomato seedlings entered the darkness, they were shone by far-red light from 20:00 to 20:10 which lasted for 10 min. In the first part of this experiment, the effects of different end-of-day far-red light intensity on tomato seedlings height and stem fresh weight were studied. The end-of-day far-red light intensity included 0, 1, 2, 4, 6, 10 and 20μmol/(m2·s). The results showed that, with the increase of far-red light intensity, the plant height and stem fresh weight increased, and when the far-red light intensity reached 10μmol/(m2·s), the plant height and stem fresh weight reached their maximum value. In the second part of this experiment, the effects of end-of-day far-red light on tomato seedling morphology, dry mass distribution, hormone content, chlorophyll content, photosynthesis rate and mineral elements content were studied. The end-of day far-red light was scheduled to last for 10 min at an intensity of 10μmol/(m2·s). The results showed that, after the end-of-day far-red light treatment, compared with the control, the plant height increased by 26.38%, the stem fresh weight increased by 15.36%, the dry mass was distributed more into stem, the content of IAA and GA3 in tomato leaves increased by 19.61% and 50.00% respectively, the content of IAA and GA3 in tomato stems increased by 42.18% and 40.00% respectively, and the content of chlorophyll and photosynthesis rate decreased by 20.24% and 13.99% respectively. The content of nitrogen (N) in stem decreased significantly, and the content of phosphorus (P) in leaf decreased significantly, while the content of potassium (K) in leaf increased significantly, and the N, P and K contents in root of tomato seedling all increased significantly (P<0.05). Phytochromes are important photoreceptors that sense red light and far-red light, and play very important role in plant growth and development. Phytochromes exist in 2 photo-interconvertible isomeric forms: the red-light-absorbing form and the far-red-light-absorbing form. After the end-of-day far-red light treatment, the far-red-light-absorbing form will quickly convert into the red-light-absorbing form, which affects the morphology of plant. Therefore, the height of tomato plants can be precisely controlled by regulating the end-of-day far-red light intensity.
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